HTTP response status is 200 but content is empty

[yanxuceo]

Hi Chris, thank you so much for this open source project. You might have heard my voice if you checked your wit.ai app for this project.

I set up my hardware and flashed this code, then it works well for "Marvin" wake-up and following "tell me a joke" "what's the life" command.

The issue is:
But when I replace the URL and access_key with my settings(which works well with curl and my local recorded .wav samples), I don't get the expected JSON content, I added this debugging line in getResults(), but the returned entities, intents and text are all empty.

if (status == 200) { char temp[1024]; int read_cnt = m_wifi_client->readBytes(temp, 1024); Serial.printf("Http str is: %s\n", temp); }

Do you possibly have any clue? I am really confused since the only difference is the replacement with my wit.ai settings. And in my app, I did receive the recorded and uploaded voice sample. But it seems that the HTTP response got something wrong.

Thank you so much for any guidance for debugging.

Best regards,
Xu

[yanxuceo]

I see, it's because now(with an update in October 2021) the /speech endpoint returns partial transcripts, which is mentioned in this issue:
wit-ai/wit#2206

[cgreening]

That's annoying. I guess we can apply the fix mentioned in that issue. I wonder why they changed it?

[yanxuceo]

Hi Chris,

thanks for the quick reply. I am new to the web stuff, but I will try to fix it. But do you have some idea, why this update has no effect on your wit.ai app(everything works well with your acess_key)? Does this API update only apply to newly created app?

Or actually your code already handles it correctly, I might make something wrong with my configuration...

I really appreciate your help.

Best regards,
Xu

[cgreening]

Hi Xu,

I need to plug mine back together - it got taken apart for a new project and I need to re-assemble it.

I'll have a look this weekend as it sounds like a simple fix.

Best
Chris

[yanxuceo]

Hi Chris, I just learned and fixed something. This is what I get on Terminal when I run:

$ curl -XPOST 'https://api.wit.ai/speech?v=20211231' -i -L -H "Authorization: Bearer my_access_key" -H "Content-Type: audio/wav" --data-binary "@apple.wav"

JSON return:
HTTP/1.1 100 Continue
Date: Sat, 01 Jan 2022 12:29:54 GMT

HTTP/1.1 200 OK
Content-Type: application/json
Date: Sat, 01 Jan 2022 12:29:54 GMT
Transfer-Encoding: chunked
Connection: keep-alive

{
"text": "Hey"
}
{
"text": "Hey Facebook"
}
{
"text": "This is Apple."
}
{
"entities": {
"fruit_type:fruit_type": [
{
//ignored
}
]
},
"intents": [
{
//ignored
}
],
"text": "This is Apple.",
"traits": {}

For this chunked return, there is no "Content-Length" in the header part. Then in the code, I added these lines in if(status == 200), which I learned from Arduino community:

    String chunk = "";
    int limit = 1;
    String response="";

    Serial.println(response);
    do {
         if (m_wifi_client->connected()) {
            m_wifi_client->setTimeout(4000);
            chunk = m_wifi_client->readStringUntil('\n');
            response += chunk;
            Serial.println(chunk);
        }
    } while (chunk.length() > 0 && ++limit < 1000);

Then, I see exact the same JSON return as it is with above curl command. So happy to see this work! I will continue to work on the deserializeJson() part. Looking forward to your fix. Thank you.

Best regards,
Xu